The method and the associated device can be used to examine different test fluids with regard to various features, contents and contamination, for example engine oils, hydraulic oils, transmission oils, brake fluids, industrial oils and cooking, baking and foodstuff oils.
The invention serves for analyzing possible damage as a result of normal or unusual wear and imminent damage in units appertaining to the automotive industry such as, for example, engines, brakes, power steering systems or transmissions and in installations, gear mechanisms, hydraulic mechanisms and controllers of industrial installations by means of the analysis of the corresponding oils or service fluids. Moreover, it serves for analyzing the quality of oils and service fluids in industry, for example the food industry, especially in kitchens.
DE 941 520 B describes a device for testing lubricating oil or similar substances with regard to an amount of foreign or discoloring constituents contained therein with the aid of an absorption spot on an absorbent paper. According to the invention, this aim is achieved by virtue of the fact that the greater portion of a sheet of paper, at its surface, e.g. by means of a color coating, is embodied such that it is comparatively non-absorbent or even repellent with respect to the substance to be tested, or the oil, and a plurality of comparatively absorbent locations are recessed in said portion, said locations having markings in the comparison color in their interior. The color comparison between a respective absorbent sample applied to a respective non-absorbent location and the associated marking for different samples is then intended to be able to be carried out very easily.
U.S. Pat. No. 5,313,824 A describes a test kit and a manual method for the analysis of lubricating oil in which a sample is applied on a test medium for a specific time and can be subjected to a visual comparison with a sample.
DE 10 2005 058 595 A1 and EP 1 825 256 B1 describe a test medium and a method for the rapid analysis of engine oils in internal combustion engines. There a drop of an oil to be examined is applied to a specific test medium and allowed to penetrate into the test medium. After a predefined time, a person carries out a manual assessment in such a way that the resulting image is visually compared with a plurality of reference images.
In the previous visual assessment by the eye of an observer, the results of the tests can be individually evaluated differently. Moreover, human eyes see very differently and perceive colorations differently. This constitutes a degree of uncertainty. Moreover, not all constituents are detected by the eye. Certain constituents in the oils to be examined cannot be identified by the eye. The method of visual assessment by the eye is only a broad-brush approach. The evaluation by the user is subject to a number of subjective influences and is learnable only with a relatively great effort in terms of practice. Human inertia also plays a part here, which often takes a critical stance toward new things. The previous methods require explanation and are training-intensive. In borderline cases the evaluation of the results is not reliable enough.
U.S. Pat. No. 5,091,652 A relates to a fluorescence scanner and more particularly to a scanner that scans gel excited to fluorescence by a laser, comprising a confocal microscope detection system.
DE 10 2005 015 826 A1 describes a method and a system for the optical inspection of contact pads on semiconductor components having different appearances. The position of contact needle tips on a contact pad can be determined by a procedure in which a first image of the surface of the contact pad is recorded before the contacting of the contact pad, a second image of said surface is recorded after the contacting of the contact pad by a contact element, and a third image is generated from the formation of the difference between the first and second images, said third image being analyzed in order to ascertain at what location the contact needle left an impression on the contact pad.
Neither of the aforementioned solutions is suitable for analyzing oils and other technical service fluids and allowing conclusions to be drawn about units from which they were taken.
EP 0 571 295 A1 describes a device for evaluating a lubricant, more particularly for a motor vehicle engine, in which a front light recording is created and is automatically assessed with regard to specific lubricant properties.
A method described in DE 196 37 234 A1 serves for online checking of the color purity of surfaces by means of a device consisting of one or a plurality of video cameras and a computer, in particular for the purpose of quality control.
U.S. Pat. No. 4,781,892 A describes an apparatus and a method for determining the fouling tendency of liquid hydrocarbons in which a front recording in the form of reflected light and a back light recording in the form of transmitted light are created. An assessment is carried out by means of the light intensity.
It is an object of the invention to propose a method and a device for the analysis of oils and technical service fluids in which the test fluids to be examined can themselves give information about the state of said test fluids and statements and evaluations regarding the mechanical-technical state of the components and units associated with the test fluids can be made. The invention is intended to afford a possibility of rapid and reliable detection, assessment and evaluation. The influence of subjective evaluation influences is intended to be reduced or completely excluded.